In an electronics system, heat may be generated as a consequence of the circuits in the electronics system having finite electrical resistance. In a computing device, significant heat can be generated by its central processing units (CPUs) and graphical processing units (GPUs). The heat being generated may relate to the amount of processing power being used. As the temperature of the computing device rises above certain threshold, it may be necessary to scale down the operating frequencies of the computing device (referred to as “throttling”) to reduce power consumption, which can degrade user experience. In extreme cases, if the temperature rises above a safety threshold temperature, it may be necessary to shut down the computing device.
For a portable computing device that can come in contact with a human body (e.g., when the device is hand-held, body worn, or placed on the lap), the heat generated by the computing device can also cause the surface temperature of the computing device to rise above a comfort threshold temperature, or in worse cases above a safety threshold temperature. For example, the UL/IEC/EN-60950 thermal safety requirements dictate that the surface temperature of a user device does not exceed 55° C.-75° C. based on the type of material used for 8 hours or more of continuous use. The comfort threshold temperature can range from 40° C. to 50° C. for user devices with metal housings.
For these reasons, it is often desirable to have an efficient thermal cooling system for a computing device.